1. Field of the Invention
This invention relates to an electrolysis cell useful for generating chlorine, and in some instances ozone, by the electrolysis of a sodium chloride solution. Such an apparatus is particularly useful for the chlorination of swimming pools, drinking water supplies, and the like.
2. Prior Art
The prior art has recognized that scale buildup is a serious problem in electrolysis cells, particularly electrolysis cells used for the production of chlorine from salt water solutions. In one relevant prior art patent, U.S. Pat. No. 3,282,823 issued to John A. Richards on Nov. 1, 1966, a pair of cylindrical electrodes are provided, one without the other, and a jet action is provided within the cell which causes gravel laden water to scour the facing surfaces of the coaxial electrodes. Such structures, however, require means for retaining the gravel in the system as well as requiring utilizing a perforate inner cylindrical electrode thereby reducing the overall effective electrode area. Also, the gravel can cause a direct short between the electrodes thus damaging them. Since complete retention of the gravel in the system is not certain, such gravel can conceivably escape from the cell to a swimming pool or the like where it could clog filters or pumps or simply form an unattractive deposit. Further, because of the escape of gravel, disassembly of the cell to replace lost gravel becomes necessary, thus increasing downtime. Still further, the interior of the cell must be relatively complex in structure to assure the proper flow direction of the gravel suspension. All of this increases the overall complexity and cost of the apparatus while providing additional potential breakdown problems.
It would be highly desirable to provide a flowthrough electrolysis cell which did not have the above disadvantages, yet which featured a fully adequate structure for abrasion of either the anode or cathode so as to prevent scale formation. In this respect, it should be mentioned that such scale formation generally does not take place at both the anode and the cathode, but rather only at the cathode whereat calcium and magnesium tend to deposit as hard water scale. Thus, it is only necessary to remove scale from the cathode since the anode will remain generally scale free in any event.